Cannot Copy Index

Hello,
I’m trying to copy an index (just settings, synonyms and rules) but I’m getting an odd http back. Has anyone seen this before. I’m using the Java API…

Snippet:
APIClient client = new ApacheAPIClientBuilder(FeedProcessor.algoliaApplicationId, FeedProcessor.algoliaApiKey).build();
Index index = client.initIndex(FeedProcessor.defaultIndexName, Product.class);

		try {
			index.copyTo(FeedProcessor.defaultIndexName + "_SM", Arrays.asList("settings", "synonyms", "rules"));
		} catch (AlgoliaException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

Error:
855 [main] DEBUG algoliasearch - Answer: {“message”:“Object must contains only destination or operation string attributes near line:1 column:54”,“status”:400}
875 [main] DEBUG algoliasearch - Got HTTP code 400
com.algolia.search.exceptions.AlgoliaHttpException: Object must contains only destination or operation string attributes near line:1 column:54

Thanks,

Simon